A number of major US hotel chain chief have called on US President Barack Obama to ensure the Dublin-based Norwegian Air's application to fly between Europe and the United States gets "immediate approval".

The chief executives of the likes of Hilton and Marriott have criticised the "inexcusable delay" in Norwegian being granted access to the market.

The letter reads:

"As the European Commission threatens formal arbitration against the United States on NAI's application, we ask that the US government quickly convene its inter-agency stakeholders to make a decision and avoid this process.

"A long, drawn-out arbitration proceeding is unlikely to serve the interests of the United States well. The timely approval of NAI's application is the right choice."

According to the Irish Independent, signatories include Hilton Worldwide chief Christopher Nassetta; Arne Sorenson, the chief executive of Marriott; Stephen Joyce, the chief executive of Choice Hotels International; and a number of US tourism and leisure group leaders.

Norwegian Air International (NAI), a subsidiary of Norwegian Air Shuttle, has been attempting to get a permit to enable it to fly between the US and Europe under the Open Skies agreement for two years. It is hoping to launch services from Cork to Boston and New York.

Despite the US Department of Transportation announcing its intention to grant a permit in April, the process has stalled.

NAI, which is currently headquartered in Dublin and employs 80 Irish staff, set up a base in Ireland in order to benefit from the Open Skies agreement.

However, there has been strong opposition to its transatlantic expansion plans from the aviation industry and politicians in the US, who believe the airline is trying to circumvent tough labour laws in Norway.